Automatic telephone-switch.



J. G, BLESSING Q B. D.'WILLIS. AUTOMATIC TELEPHONE SWITCH. 'APPLICVATIOI m n I". 10. 1912/ 1,256,511. mm Fb. 19,1918.

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1. e. mssme .11. WILLIS.

AUTOMATIC TELEPHONE SWITCH.

I APPLICATION FILED IA". 15, I912- 1,25 ,511, v Patented Feb.--19, 191s.

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.l. GJBLESSING & B.. D. WILLIS, AUTOMATIC TELEPHONE swmm.

' ABPLICATIOI FILED HAL l6. 1912- 1,256,51 1. Patented Feb. 19,1918

s. BLESSING & B. o; WI LL|S. AUTOMATIC TELEPHONE SWITCH.

APPLICATION FILED MAR. I6. I912. 1,256,511. Patented F b ls, 191s.

5 SHEETS-SHEET 4.

e. alassme'a B. u. WILLIS.

, AUTOMATIC TELEPHONE SWITCH.

APPLICATION FILEQ QIAII. I6. 1912. 1366;511. Patented Feb. 19,1913.

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UNITED STATES PATENT OFFICE.

JOHN G. BLESSING AND BERNARD D. WILLIS, OF CHICAGO, ILLINOIS, ASSIGNOBS TO AUTOMATIC ELECTRIC COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

AUTOMATIC TELEPHONE-SWITCH.

Specification 0! Letters Patent.

Application filed March 16, 1912.- Serial'No. 684,110.

To all whomit may concern:

Be it known that we, JOHN G. Bnassmo and BERNARD D. WILLIS, citizens of the United States of America, and residents of Chicago, Cook county, Illinois, have invented certain new and useful Improvements in Automatic Telephone-Switches, of which the following is a specification.

Our invention r;iates to automatic or emi-automatic-telephone systems, and more particularly to an iniproved automatic switch and circuits for operating the same.

The objects of our invention are to devise a switch which is capable of being operated at a very high rate of speed, andone in which there is very little wear upon the operating parts. The speed of operation 1 of the ordinary step-bystep switches is li1nit-ed by the speed at which the armatures of the operating magnets which control the. operating pawls vibrate. In our improved switch-however, the only parts which operate-intermittently in synchronism with the operating impulses are the line relay and a small escapement wheel. These parts are made very light and can, therefore. be operated very rapidly. Thev shaft, however, of our switch moves with a uniform motion, which motion is controlled by the intermittent operation of the line relay. The motion of this shaft. is controlled by a governor. while the motion of the line. relay and the escapcment is uncontrolled. wherebv the line relay and escapement operate with a greater rapidity than the operating shat t.

A further object. of our invention is to devise a switch having, vertical and rotary motion. the vertical selecting motion of which is downward instead of upward, as in the usual type of Strowger switch.

Another object of our invention is to devise a switch in which the power for the. selecting operation of the switch is supplied from an operating: spring, and one in which the same source of power is used to control the. downward and rotary motions of the switch. llcretofore it has been necessary to apply separate operating means for operating the switch in its two selecting motions, but in our improved switch we provide a single operating means which normally tends to move the switch wipers in a vertical direction, and when prevented from moving them in this direction tends to rotate the. wipers.

These and other objects of our invention will be more readily understood by reference to the accompanying drawings, in which we have illustrated our invention in connection with a full automatic two-wire system comprising line switches, first and second electors and connectors, and in which Figure 1 is a front elevation of a switch embodying the principles of our invention.

Fig. 2 is a rear view.

Figs. 3 and 4 are side views of the same.

Fig, 5 is a detail view of a portion of the apparatus.

Figs. 6 and 7 show a complete connection between a calling and a called substation.

The switch shown in Figs. 1,2,3 and 4 resembles the switches shown in United States Letters Patent Nos. 815,321 and 815.176,

granted March 13,1906, to Keith, Erickson and Erickson, in that it comprises a bank of contacts which are adapted to be and usually comprise ten horizontal rowsof contacts wlth ten contacts in each row. The shaft 6 is mounted in the bearings 7 and 8 upon the front of the plate 2. On the lower end of the shaft there is shownone wiper 9. It will be understood that there may be a plurality of wipers attached to the shaft and a separate bank of contactsprovided for each wiper. Loosely mounted upon the shaft 0 there is a cylinder 12. There is a pin 13 on the shaft 6 which extends through a slot 14 in the cylinder. On the back of the cylinder 12 there isa series of gear teeth 15 which mesh with a gear wheel 16 on a shaft 17. Loosely mounted on the shaft 17 there is a gear wheel 18 which meshes with a pinion 19 on a second shaft 20. On the side of the wheel 18 is a pawl which is adapted to engage a ratchet on the shaft 17. so that the wheel 18 is forced to rotate with the shaft in one direction but not in the other. Loosely mounted upon the shaft 20, but connected therewith by the spring 21, is an escapement wheel A pin 23 projects horizontauy from the face of the wheel 22 into the path of'a pin 24 on the shaft 20. The escapement lever of the escapement wheel 22 is controlled by the relay 25, asshown in" F ig. 5. Secured to the shaft 20 there is also a gear wheel which engages a worm gear of a governor comprising a pair of weighted springs 26 and a stationary cup 27. As the s aft 20 rotates, the sorings 26 revolve and their ends fly out ant rub on the inside of the cup 27 thereby producing a braking action to limit the speed of operation of the switch. On'the back of the plate 2 there is a solenoid 30, the plunger 31 of \Vlll('ll iS provided with gear teeth which mesh with the pinion 32 on the shaft 17. On the top of the plate 2 there is a sliding catch 34 which is adapted to engage the teeth 35 on the upper end of the shaft 6. This catch is normally held out of engagement with these teeth, against the tension of the spring 39, by a pin on the back of the cylinder 12, which in engages the arm 41 of the lever 36.

'QVhen the cylinder 12 is lowered, the arm 37 of the lever 36 engages the armature of the relay 38 and still holds the catch 34 out of engagement with the teeth on the shaft until the relay 38 is energized. On the back of the switch there isa set of springs 42, 43 and 44 which are controlled by a disk 45, composed of insulating material, upon the shaft 20. This disk has notches in lts sides which, when'they are opposite the springs 42 and .44, permit them to come into contact with the spring 43. When the relay 25 is deenergizedthat is, when the escapement wheel 22 is heldby the engagement of one of its armswith the arm 51 of its escapement lever--', the shaf 20 is held in position for the spring 42 to engage a notch in the disk 45. When, however, the relay 25 is energized and the escapement wheel 22 is held by the engagement of one of its fingers with the arm 52 of the escapement lever, the disk isheld in osition for the spring 44 to drop into one of the notches in its side of the disk. Although one of the notches normally stands opposite the spring .42, said of engagement with the sprin .43 by the lever 53 and the spring 54. n the back of the switch there 1s a slow acting relay 61,

I the armature of which is adapted to engage the escapemcntwheel 22 to lock-the mechanism when the relayfil is energized.

Besides controlling the escape'ment wheel 22, the relay 25'also controls. a pair of contact sprin s 57 and 58. The s rings 59 and 60 are controlled by a pinonthe wheel 16 in sucha manner that they are closed whenever said wheel is out of normal position. In general, the operation of the switch shown in Figs. 1, 2, 3 and 4 is as follows;

.The cylinder 12 is normally held in its up positiom. as shown in the drawings,

against gravity and the tension of a spring spring is held out sire rows of contacts.

33 on the shaft 17, by the engagement of one of the fingersof the wheel 22 with the arm 51 of its escapement lever, whereby the whole mechanism is locked. The shaft 6, being free, rests with the pin 13 at the bottom of the slot 14, in which position the wiper 9 (Fig. 1) rests three steps above the upper row of contacts in the bank 3 and two steps out of line with the first contacts. When connection is extended to the switch, the relay 25 is energized, thereby allowing the escapement wheel 22 -to advance one step, or.one-sixth of a revolution, when one of its arms will come into contact with the arm 52 of the escapement lever. This allows the shafts 20 and 17 to rotate a corresponding amount, permittingthe cylinder 12 and the shaft 6 to descend one step. When the cylinder is thus lowered, the pin 40 (Fig. 2) strikes the lug 55 on the upper end of the lever 53, forcing it out so that the projection 56 on the arm 41 (Fig. 1) drops behind it and holds the lower end of the lever 53 out of engagement with the spring 42; but since the shaft 20 has been rotated, the

spring 42 rests on the flat surface of the disk 45 and out of engagement with the spring 43. Upon the first movement of the switch the pin in the wheel 16 permits the springs 59 and 60 to close. If now, the relay 25 be denergized momentarily a number of times, the escapement wheel 22 will be permitted to rotate step by step. As soon as thewheel'22 advances the first step, the in 23 leaves the pin 24 and unlocks the sha t 20. I The shafts'17 and 20, therefore, begin to rotate to lower the cylinder 12 and the shaft 6. Since the escapementwheel 22 is rotated on the shaft 20 by the spring 21, it advances instantly whenever the relay 25 is energized or de'eInergized. The shaft 20 is, however, controlled by the, governor springs 26, so that it rotates more slowly that the wheel 22. Therefore, if the relay 25 is energized and deenergized rapidly, the pin 24 will notbe able to'catch up with the pin 23, and the shaft 20 will rotate continuously to lower the shaft 6 with a uniform motion as long as the relay 25 is operating. The spaces between the rows of contacts in the banks 3 are equal to the distance'through which the shaft is lowered by the steps of the escapement wheel 22' that is, therr'elay 25 must be denergized and. energized again'i'n order to'permit the shaft to be lowered the distance between succes Therefore, when the mechanism finally comes to rest, with the relay 25 m an energized position, the wiper 9 W111 be standing opposite the row of bank contacts which corres 0nd to the number of timesthe relay 25 lids been deenergized. During the time the shaft 20 is rotating to permit the cylinder 12 to be lowered. the notches in the disk 45 pass the end of the springs 42 and .44 so rapidly that 'these' springs do not have a chance to drop into contact with the spring 43. When, however, the mechanism comes to rest, with the relay 25 energized, the spring 44 drops into a notch and into enga ement with the spring 43. This energizes t erelay 38, which releasesthe lever 36 and permits the catch 34 to be drawn into engagement with the teeth 35. If, now, the re ay 25 be again deenerized rapidly a number of times, the cylinder 12 will be again lowered in the same manner as previously explained. Since the catch 34 is in engagement with the teeth 35, the shaft 6 cannot descend with the cylinder and will therefore be caused to rotate, due to the action of the slot 14 'on the pin 13, This slot is so shaped that when the shaft 6 cannot descend and the cylinder 12 is lowered, the movement of the cylinder, caused by the deenergization and energization of the rela 25, will rotate the shaft. to carry the end of the wiper 9 a-distance equal to the dis tance between successive contacts in the rows of the bank 3. Therefore, if the rela 25 is momentarily denergized a number 0 times while the catch 34 is in engagement with the teeth 35, the wiper 9 will be rotated over the contacts in the row corresponding to the particular tooth 35 with WhlCll thecatch 34 is in engagement, and the contact in the row u on which' the wipers will come to rest will epend upon the number of times the relay 25 is deenergized. During this rotary operation, the spring 44 is held out of engagement with the spring 43 in the same manner as during the downward motion, and the spring 44 again engages the spring 43 when the shaft 20 comes to rest upon the termination of the rotary operation. It will be seen that when the shaft 17 rotates to permit the cylinder 12 to be lowered, it also raises the plunger of the solenoid 30 the same distance. In order to restore the apparatus to its normal position the solenoid 30 is energized, thereby pulling down the plunger 31 and restoring the shaft 17 to its norn'lal, )osition. During the restoration of the shaft 17, the wheel 18 remains stationary. due to the operation of the ratchet and pawl heretofore described.

In order to give a clearer understanding of our invention, we will describe in detail howa connection is extended from the substation A (Fig. 6) to the substation A" (Fig. 7), in which the connector switch Il. (Fig. 7) is of the type of switches shown in Figs. 1, 2, 3 and 4. In Fig. 6 the line of the substation A is shown terminating at thelcentral otlice in an individual or line switch C. At 1) there is shown a master switch for controlling a group of line switches (1. The

line switches of this group have common access to anumberof trunk lines which lead to first selectors E. A number of first seleca ble automatic common battery type. h'ei'oin shown it comprises the usualretors have common access to a number of second selectors F (Fig. 7), which in turn have access to connector switches H by means of which connection may be completed with subscribers lines. Associated with the connector H there are shown a ringing current generator M and a busy signaling apparatus L. At B a battery is hown having one terminal grounded. The automatic substation A may be of any suitceiver, 66, transmitter 67, ringer 68 and switch hook 69. Being an automatic substation itis also provided with an automatic calling i'device herein represented by a pair of impulse springs 70 and 71 and a toothed impulse Wheel 72. .The impulse wheel 72 is secured to a shaft 73 to which there is also attached a dial (not shown) provided with finger holes. Through the medium of the dial the subscriber may cause the impulse wheel 72 to separate the springs 70 and 71. any desired number of times to call any digit.

The line switch C, which is individual to the line of the substation A, and the master switch D. are modified forms of the general type of line switch and master switch disclosed in Br'Etish'Patent No. 26,301 of 1906, but, however, of the particular type shown in British Patent No. 1,419 of 1910. As herein represented, the line switch C com prises, amon other details, a plunger (not shown) attac ed to the end of the socalled plunger arm 74 which. is controlled by the magnet 75. The magnet 75 also controls the relay arinatures 76 and 77 and is composed of four windings, namely, a pull-in winding 78, a holding and cut-oft winding 79, a line 105 winding 80 and an auxiliary winding 81. The core of the magnet is provided near the center of its length with a lateral projection 82 by means of which the magnet is mounted upon the bracket-83, upon which latter the 110 armatures 74, 76 and 77 are pivoted. W'ith this method of mounting the magnet, the magnetic circuit of the windings 78 and 79 is maintained separate from that of the windings 80 and 81, so that the armatures 5 springs, fm'cing the springs 84, 86, 88 and 90 into contact with the springs 85, 87, 89 and tll respectively. Although only one set of springs (84-91) ls shown, each line switch C is provided with a number of such groups of springs, each group forming the terminal of a trunk line leading to a selector E. Each trunk line is multipled to the corresponding;

springs of all of the line switches of the,

group which is controlled by the master switch D.

The plungers of the line switches normally engage a socalled plunger shaft (not shown), and through the medium of the master switch D are normally maintained opposite the terminals of an idle trunk line. The master switch consists essentially of a motor magnet 92 for rotating the ratchet wheel 93. The ratchet wheel 93 is connected with the plunger shaft in such a manner that a. rotary motion of the wheel imparts an oscillatory motion to the shaft to move the plunger-s back and forth in front of their trunk terminals. To the plunger shaft there is also secured a locking plate 96 provided with a number of openings adapted to be engaged by the pin 94 upon the end of the armature The holes in this plate are so spaced that the pin 94. can engage one of them and allow the armature 95 to resume its normal position only when the idle plunrs are directly opposite a trunk terminal.

he masterswltch is also provided with a bank of contacts com risinga common segment 07 and one in ividual contact a' for each trunk line to which the line switches have access. The wiper 98 always keeps the common segment 97 in contact with the individual contact of the trunk line before which the plungcrs are resting. The selector E is of the general t pe of selector switch disclosed in Patent o. 815,321 hereinbe-' fore referred to. Among other details, the selector E comprises a set of wipers 99, 100 and 101 carried upon a vertically. and rotatably movable shaft (not shown). The vertical movement is controlled by the vertical magnet 102 and the rotary movement is controlled by the rotary magnet 103. The usual vertical and rotary line relays are replaced by the double-wound line relay 104. The slde switch, comprising the wipers 105 and 106, is controlled by the private magnet 107 in a manner well known in the art. Means for restoring the switch to normal position are provided in the release magnet 108. This magnet-releases the switch immediately upon energization rather than by deenerglzation as shown in the said selector patent. The springs 109 are opened by the switch shaft whenever it is in its lowest position.

T he selector F is the same as the selector 1).

As hasbeen previously explained, the connector H is the same as that shown in Figs. 1, 2, 3 and 4, portions of the mechanism being represented diagrammatically. As shown in Fig. 7, the connector is provided with three wipers, namely, a so-call'ed private wiper 9 and two line wipers 10 and 11. A

ringing relay 110 is shown also in Fig. 7. Since this relay has no connections with the mechanical parts of the switch, it may be mounted at any convenient place upon the frame.

The line switch C and the substation A are in all respects the same as the line switch (3 and the substation A.

When the subscriber at substation A removes his rec'eiver preparatory to making a call, a bridge is closed across the line conductors 111 and 112 through the transmitter 07, receiver 66 and impulse springs and 71, thereby closing a circuit through the line winding 80 of the line switch C. This circuit extends from ground G through the springs 113 and 114., line 111, telephone A, line 112, springs 115 and 116 and the Winding 80 to the battery lead 117. The winding 80, upon energizing, attracts the armature 77, thereby closing a circuit from ground G through the springs 113 and 118, windings 78 and 81, contact 119 and the armature 95 to the battery lead 117. The winding 78, upon energizing, attracts the plunger arm 74 and cut-ofl' armature 76. The-plunger arm, upon being attracted, causes the plunger to close the springs 84-91 into contact in pairs as indicated. The closure of contact between the springs 84 and 85, and 86 and 87 extends the line connection to the first selector E, whereupon its line relay be comes energized over a circuit extending 'from ground G through the lower winding of the relay 104, spring 120 and its back con tact, line switch bank springs 87 and 86, thence to andthrough the telephone A and back over the other side of the line through the springs 8-1 and 85, spring 121 and its back contact and the upper winding of the relay 101 to the battery lead. The relay 104, upon energizing, completes a circuit from ground Gr through the spring 122 and its front contact and the relay 1523 to the battery lead. The relay 123, upon energizing, completes a circuit from ground G through the springs 124, line switch bank springs 89 and 88 and the .winding 79 to the battery lead. The winding 79, upon energizing, operates to hold the arn'iatures 74 and 76 in their operatedpositions after the winding 78 is deenergized. The winding 78 is deenergized by the falling back of the armature 77, which occurs shortly after the line winding 80 is disconnected from the line by the operation of the cut-off armature 7 (i. In order to delay the falling back of the armature 77 a short time so as to give the winding 79 a chance to become energized, the winding 81 is provided on the lower end of the magnet 75. This winding 81 is energized in series with the operating winding 78, and is short-circuited bv the closure of the contact 125 when the plunger arm reaches its fullyoperated posltion. This momentary energization of I the winding 81, and the short-circuiting thereof, keeps the arinature 77 attracted for an instant after the winding 80 is' disconnected from the line. The ener ization of the relay 123 at the selector E a so extends ,a guarding potential 1 from ground G through the springs 124, 89 and 88 and over the conductor 127 to the connector private bank contacts of all the connectors which have access to the line of substation A. The closure of the bank springs 90 and 91 of the line switch C completes 'aycircuit from ground G through the springs 90 and 91, contact 128 (which it is assumed corresponds to the trunk line leading to the seledtor E), wiper 98, segment 97 and the relay 129 1; battery. The relay 129, upon energizin closes a circuit .through the relay 130. he relay 130 thereupon attracts its armature 95, withdrawing the pin, 94 from the locking plate 96 and closing the circuit 'of the motor magnet 92 at the contact 131. Since the circult of the motor magnet includes the interrupter springs 132, said magnet will operate in a manner similar to that 01" a buzzer as long as the contact 131 is closed, thereby rotating the ratchet wheel 93-step by step to'advance the plungers of the idle line switches away from the trunk seized by the switch After the'plungers have advanced a short distance, the wiper 98 is disengaged from the contact 128 and the relays 129 and 130 denergize.

. The contact 131, however, remains closed until the next opening in the plate 96 passes under the pin 94, whereupon the armature 95 resumes its normal position, breakin the circuit of the motor magnet 92 and loc ing the plunger shaft. If the next trunk after the onefseized by the line switch had been busy, the wiper 98 would have found a guarding potential upon the corresponding contact in the master switch bank, and the relays 129 and 130 would have remained energized while the next opening in the plate 96 was passing under'the pin 94, and therefore the plungers of the idle line switches would have been carried past the busy trunk to an idle one.

The .foregoing operations take place immediately upon the removal of the receiver at the calling substatio'n. The culling subscriber now operates his calling device for the first digit of the number to be called, which will be assumed to be 2220. The operation of the calling device for the first digit 2 momentarily separates the substation impulse springs and 71 twice. Each time these springs are separated the first selector line relay 104 dei ncrgizcs. Since the relay 123 is slow to dei nergize, its armature does not. have time to fall back during the momentary interruption of its circuit by the relay 104, 'lhereforo, caclrtime the relay 104 dei ucrgizes a circuit IS closed from ground G" through the spring 122 and its 'back contact, spring 133 and its front contact, relay 134 vertical magnet 102 and the side switch wiper 105 to the battery lead. The two impulses received over this circuit cause the vertical magnet to raise the shaft wipers 99, 100and 101 two. steps to a position opposite the second row or level of bank contacts. The relay 134, which is included in the operatingcircuit of the Yertical magnet, when energized, closes a circuit from ground Gr through the springs 135 and the private magnet 107 to battery. The relay 134, being slow 'actin does not have time to deenergize until a ter the last impulse is delivered to the-vertical magnet. When it does denergize, the relay 134 breaks the circuit of the private magnet 107, which in turn denergizes and permits the side switch to pass to second position. In second position the side switch wiper completes a circuit from groundG through the interrupter springs 137, rotarymagnet 103 and the side switch wiper 105 to the battery lead. As long as the side switch re mains in second position the rotary magnet operates in a manner similar to that of a buzzer to rotate the wipers step b step over the bank contacts of the 'secon level, to which level they were raised by the vertical magnet. Each time the rotary magnet is energizedit closes the contact 138, thereb completin a circuit from ground through t e private magnet 107. If the first trunk line is idle, the first. impulse through the private magnet steps the side switch to third position, thereby breaking the circuit of therotary magnet and leavin the wipers standing upon the contacts 0 this first trunk. If this first trunk line is busy, however, the private wiper 101 finds 105 its private bank contact grounded, and com-' pletes a holding circuit through the side switch wiper 100 (in second position) and the private magnet '107 to battery. This holdingcircuit through the private magnet causes the side switch to be locked in second position, whereupon the 'rotary magnet. 103 continues to advance the wipers until an idle trunk is found, whereupon this holding circuit of the private magnet 107 is broken This circuit extends from ground G at the relay 123 through the springs 124, relay 139 and the side switch wiper 105 'to battery. The relay 139, upon energizing, disconnects the line relay 104 from the line and extends the line connection through the line wipers 09 and 100 to the second selector F, whereupon its line relay 140' becomes energized -in the same manner in which the'relay 104 was energized when the connection was first extended to the selector E. The relay 1'40, upon energizing, closes the circuit of the relay 141. The relay H1, upon energizing, completes a circuit extending from ground it throughthe springs 142, private bank contact and private wiper 101 of the selector E, side switch wiper 106, thence through the relay 139 and the holding winding 79 of the line switch in multiple to battery. This circuit just'traced for thepurpose of maintaining the relays 139 and 79 energized after the relay 123 of the selector E is tlei nergized, which occurs shortly after the relay 104 is disconnected from the line by the relay 139.

The calling subscriber now operates his calling device for the second digit 2, whereupon the second selector F operates in the same manner as explained for the selector E to extend the connection over the trunk conductors 144 and 145 to the connector H (Fig. 7). The line relay 25 of the connector thereupon becomes energized over a circuit extending from ground ti through the lower winding of the relay 25, spring 14-7 and its back contact, trunk conductor 145, thence over the heavy conductors to and through the substation A, back over the other side of the line through the switches E and F, over the trunk conductors l th springs 149 and g 150 and the upper winding of the relay 25 to battery. The relay 25, upon energizing, permits the escapcment wheel 22 to advance one step, as has been already explained, whereby the switch shaft 6 is lo i'ered a short distance and the wheel 16 (Figs. 2 and 3) permits the springs 59 and 50 to come into contact. The closure of these springs provides a new holding circuit for the relays 153 and 13!} of the switches l" and E and the winding 79 of the line switch (7. This circuit-extends from ground (l through the springs 60 and 5!). conductor 146. private wiper 151 of the selector F, side switch wiper 152 and thence through-the relays 153 and 139 and the winding 79 in multiple to battery. When the calling subscriber opcratcs his calling device for the third digit. 2. the line relay 25 of the connector ismomcntarily dci nergiztal twice and then brought to rest in its energized position. As has already been explained, these two dci ncrgizations of the relay 25 permit the switch shaft to be lowered a sullicicnt amount to bring-the wipers 9, 10. and 11 opposite the second row or level of bank contacts, counting from the top. Also, as has been previously explained,

the disk 45 rotates contimuulsly during the downward movement of the shaft and at such a. spccd that thc springs 42 and 44 do not have a chance to come into contact with the spring 43.- Aftcr the impulses are delivcrcd. however, the disk 15 cmucs to rest in a position in whlchtluspring 4+ drops into a notch and engages the spring 43. A

circuit is thereby closed extending from ground G through the springs 60 and 59, relay 38, lower winding of the. relay 154 and the springs 4-1 and 43 to battery. The relay 15 1 is not energized over this circuit, due to the comparatively high resistance of the relay 38. The relay 38 is energized, however, and releases the catch 31 (Fig. 1), allowing it to engage the teeth in the shaft. Now, when the substation calling device is operated for the last digit 0, the line relay 25 is det nergized ten times, and since the shaft is locked against further vertical movement, it is forced to rotate in the manner heretofore explained to carry the wipers 9, 10 and 11 onto the tenth, contacts of the second level, which are the contacts of the line desired. During this rotary operation the spring 44 is disengaged from the spring 43 and the relay 38 is allowed to dciinergize. When, however, the disk 15 comes to rest after the last impulse is delivered, the 5 ring 44 again engages the spring 43 and tie relay 38 is again energized. The closure of the contact between the springs 155 and 156 and 157 and 158 of the relay 38 completes the line connection through the line wipers 10 and 11 to the called substation. The rclay 38, upon energizing, also provides a guarding ground potential for the connector private bank contact of the called line and an energizing circuit for the ringing-relay 110' and cut-off winding 159 of the line switch 0. The guarding potential for the private bank contact and the energizing circuit for the winding 15'!) extends from ground G through. the springs 160 and 161, private wiper 9. thence to the connector private bank contacts of the called line and through the winding 15$) to battery. The winding 159, upon energizing. attra ts the armature 164, which operates to disconnect the switch t'rcm the called line and to close the normally open cpntact 163 in the talking circuit. The circuit, for the ringing relay 110' extends 'irom ground (l through the springs ltjt) and 16:2, springs 165 and 166, relay 110 and the interrupter 167 to battery. The ringingrclay 110. upon energizing, disconnects-the calling from the called line. and connects the ringing generator M with the called line to signal the called subscriber. Since the circuit of the ringing relay contains the interrupter 167, thesaid relay is energized cnlv intermittently so as not to ring the called subscriber continuously. \Vhen the talking circuit is bridged across the called line by the removal of the receiver at the substation A. or as soon thereafter as the relay 110 dci ncrgizes. if it happens to bc energized at the time. a circhit is closed through the back-bridge relay 168 of the connector. This circuit extends from ground G through the lower winding of the relay 1G8, springs 157 and 158, ringer I throu relay s rings 169 wiper 11 thence to and the substation A' and back over the ot er side of the line through the wipe;

1 10, ringer relay springs'170, springs 1 56 an 155 an the upper windingo the relay 168 to battery.' The closing of the springs 171 by the energizing of the relay 168 completes a circuit from round G through the springs 171 and t e upper winding of the relay 154 and springs 44 and 43 to battery. The relay 154, upon energizing, breaks the circuit of the ringing relay 110 at the springs 165 and 166, thereby cutting off the rln 'ng current and allowing the two subscri ers to carry on an interrupted conversation over the talking circuit outlined by heavy conductors in the drawings. The 're-.

lay 154, upon energizing, closes a locking circuit for itself extending from groundGr through the springs 160 and 162,165 and 173 and the upper winding of the relay 154 to battery. The closure of this locking circuit prevents the relay 154 from falling back and again closing the energizing circuit of the tated in case the calling subscriber should again operate his calling device for any reason. It will be seen that after the relay 61 in energized, a'second circuit is closed extending from ground G through the springs 174, relay 61, springs 175 and the line relay springs 57 and 58 to battery.

Therefore, if the calling device is again operwted, the relay 61 will receive an lmpulse of current each time the line relay is energized, even though the springs 44 and 43 are separated. The relay 6], bein slow acting, does not have time to denergize between these impulses, and therefore the shaft remains locked.

It will be seen that when.the back-bridge relay168 is energized upon the response of the called subscriber, it interchanges the I connections between the windings ofthe line relay and the conductors 144 and 145. This,

it will be seen, reverses the direction of the current flowing in the calling line. This reversal of current may be used for the purpose of operating call register devices on the calling line, or for controlling supervisory signals in an operators cord circuit in case the connection is a semi-automatic one.

The connection is released upon the te mination ofthe conversation by the hanging up of the receiver at thecalling telephone.

The hanging up of the receiver permits the relay 25 to definerg'ize. This permitss'the disk v 45 to rotate sutliciently to open the springs 44 and 43 and to permit thespring 42 to drop into the notch and engage-the spring 43. The circuit'of therelay 61 is, also broken by the denergization of the relay 25,

and as soon as this relay deiinergizes, a circuit is closed through the restoring solenoid 30. This circuit extends from ground G" through the sprin s 60 and 59, solenoid 30, springs 176 and 1% The solenoid, upon energizing, restores the mechanism of the connector to normal ition, as has been already described, on thecorinector reaches its normal position, the springs 60 and 59 are separated thereby breaking the circuitof the solenoid and the holding circuit of the rela s 156 and 139 ofthe selectors F and E an the winding 79-of the switch C. The winding 79, upon denergizing, permits the plunger of the line switch to be restored to normal position. The denergization of the relay 139 of the selector E completes a circuit extending from ground G through the spring 122 and its back contact, spring 133 and its back contact, springs 179 and 109 and the release magnet 108 to battery. The magnet 108, upon energizing. restores the selector to normal position, and when the switch shaft reaches its lowe$ position, the s rings 109 are ac arated to allow there ease magnet to eenergize. The selector F is released in the 'same manner as the selector E. I ,It having been explained'how the connector- H may connect with. an idle line, it remains to be'explained how the calling subscriber is given the busy signal in case the called line is busy. Whenever a-line is busy, its. connector private bank ,contacts' are 7, 42 and 43 to battery.

grounded. Therefore, when the wiper 9 strikes the contact of a busy line, a circuit is closed from the grounded private bank contactof said line through the springs 161 and 180, lower winding of the relay. 154,-hnd the springs 44 and 43 (when the 'diakfy'fli comes 'to' rest) to battery. -The-j:cl l gsu,re; of I this circuit energizes therelay 154,-1apll the;

relay 38 remains define becausegfiit' is short-circuited by the ground atjtheprivate bank-contact of the busyline. relay B8 isnot energized the connectionis not completed between the callingand- -the called lines, and the closing of the contacts 181 at the relay 154 extends a-.connectiony" from-the busy signaling machine L through said springs-181, springs 182 and 157,;c0n-,-

denser 1'83, thence to and through the sub station A, theme back 'tofflie connector,

through the lower winding of- .tlie'fline relav 25 to. ground G, thence as the hatter and back to the other terminal of the usfy signaling machine.

rent flowing over this circuit signifies to the.

The busy signaling cur plained when it was energized upon the response of the called subscriber. The lockmg of the relay l54= is for the purpose of preventing it from deenergiZing-and cutting on the ringing current in case the busy guarding potential should be removed from the called line before the calling subscriber A hangs up his receiver and releases the connection.

W'hllc we have shown and described one specific embodiment ol' our invention, it

'will be understood tha; we do not wish to vlimit ourselves to such exact construction,

'as manychanges will r--adil v suggest themselves to anyone skillwi in. the art. Furthermore, it is evidem that our improved switch is equally well apted for use in a semi-automatic System Jo which manual operators are employed r .-=ssist.ing in the establishin 'of connection be ween calling and called su scribers lines.

What we claim as our Invention is:

1. In a telephone system an automatic selecting switch provided. with a shaft. carrying wipers, said shafthovmg downward and rotary selecting motions, and circuits for operating the same.

2. In a tele hone system, an automatic selecting switcii having downward and rotary selecting motions, and means for controlling said switch over the two sides of a metallic talking circuit inseries.

3. "In a telcphone' system, lines divided into groups, an automatic switch having downward straight line motion to select groups and rotary motion to find a line in the selected group, and circuits for operat ing the same. 4. In a telephone system, lines divided into groups, an automatic switch having downward motion to select groups and ro tary motion to find a line in the selected group, and means for controlling said switch over the two sides of a metallic talking circuit in series.

5. In a telephone system, an automatic switch including an element movable in two intersecting lan( s.-means for moving said element by a.-i-.'t'intinnousmotion, stcp-by-step means for'conlrolling lhe extent of operation of said movable element, and circuits for coi-itrollil'lg said operation.

(5. In atelephone system, an automatic switch including a movable element, means for moving said element by a continuous motion. and step-by-slep means controlled over the two sides, ol" a metallic talking cir cult in series for controlling the extent of operation of said movable element.

movable in two intersecting planes, means onsaid subscribers line for transmitting a varied number of impulses to control said switch, means for moving said arms vby a continuous motion, and means controlled by said varying number of impulses for controlling the extent ofmotion of said arms.

8. In a telephone system, a subscribers line, an automatic switch including movable arms, means on said subscribers line for transmitting a varied number of impulses over the two sides of a metallic talking circuit in series to control said switch, means for moving said arms by a continuous motion, and means controlled by said varying number of impulses for controlling the extent of motion of said arms.

'9. In a telephone system, an automatic switch including movable arms, means for moving said arms by a continuous motion in two intersecting planes, step-by-step means for controlling the extent of motion of said movable arms, and circuits for controlling said operation.

]0. In a telephone system, an automatic switch including movable arms, means for moving said arms by a continuous motion in two intersecting planes. and step-b v-step means controlled over a metallic circuit for controlling the extent of motion of said movable arms.

11. In a telephone system, an automatic switch including movable arms, means for moving said arms by a continuous motion downward, means .for controlling the exmotion. and circuits for controlling said operation. 1

12. In a telephone system, an automatic switch, means for transmitting a varied number of impulses to operate said switch, movable arms for said switch, means for movin said arms downward by a continuous motion. means controlled by said impulses for determining the extent of motion of said arms, and means for then rotating said arms.

13. In a telephone system, an automatic switch, means for transmitting a varied number of impulses over a. metallic circuit to operate said switch, movable arms for said switch. means for moving said arms downward by a continuous motion, means controlled bv said impulses for determining the extent oi moi ion of said arms, and means ior then rotating said arms.

14. In a telephone system, an automatic switch including an operating shaft, means for controlling the opcratiouof said'shat't, and means for simultaneously operating said controlling means at one. speed and aid operating shaft at. a second speed.

15. In a telephone system. an automatic switch, an operating shaft therefor, an escapement mechanism for controlling the operation of said shaft, means for operating said escapement mechanism at one speed, and means for operating said shaft at a second speed.

16. In a telephone system, an automatic switch, an-operating shaft therefor, an cscapement mechanism controlling the extent (if operation of said shaft, a governor for controlling the speed of said shaft, whereby, said 'escapement mechanism is adapted to operate at a higher rate of speed than said shaft, and means including electricalcircuits for controlling the operation of said shaft.

17. In a'telephone system, an automatic switch including a movable element having motion in two intersecting planes a single operating means for moving said element in both of said planes, and electrical circuits tor controllin said operating means.

18. In a tefiephone system, -an automatic switch including a movable element having motion in two intersecting planes, a single operating means for moving said element in both of said planes, and means for controlling said operating-means over a metallic circuit.

-19. In a telephone system, lines divided into groups,,an automatic switch including 'a movable element having motion in one plane to select groups and motion in a plane at right-angles thereto to find a line in the selected group, and a singlepperating means for moving said element in both-of said planes.

20. In a telephone system, lines divided into groups, an automatic switch including a movable element having motion in one plane to select groups and motion in a plane at right-angles thereto to find a line in the selected group a single operating means for moving said eiement in both of said planes, and means for controlling said operating means over a metallic circuit.

21. In a telephone system, an automatic an itch including a movable element having motion in two intersecting planes,"a single spring-for moving said element in both of said planes during the operation of said switch, and electrical circuits for controlling the operation of said switch.

22. In a telephone system, an automatic switch including a movable element-having motion in .two intersecting planes, a single spring for moving said element in both of said planes during the operation of said switch, and means for controlling said switchover a metallic circuit 23.";In a telephone system, lines divided into groups, an automatic switch including a movableelement' having motion in one ,plane to select a group and motion in a plane {pt right-angles thereto to find a line in the selected group, and a single spring Ior moving said element in both of said planes during the operation of said switch.

24. In a telephone system, lines divided into groups, an automatic. switch including a movable element having motion in one plane to select a group and motion in a plane at right-angles thereto to find a line in the selected group, a single spring for moving said element in both: of said planes during the operation of said switch, and means for controlling said switch over a metallic circuit.

25. In a telephone system, an automatic switch including a movable element, operating means tending normally to. operate. said element in one direction, and operating the same in another direction when prevented from moving it in the first-mentioned dircction, and electrical circuits for controlling the operation of said switch.

26. In a telephone system, an automatic switch including a movable element, and opcrating means controlled over a metallic circuit tending normally to operate said-element in one direction, and operating the same in another direction when prevented from moving it in the first-mentioned direction.

27. In a telephone system, an automatic switch including a movable element, an operating spring normally tending to move said element in one direction, means con-.

trolled by said spring for moving said element in a direction at right-angles to said' first-mentioned direction when motion in said direction is prevented, and electrical circuits for controlling the operation of said switch.

- 28. In a, telephone system. an automatic into groups, an automatic switch including a movable element, and operating means tending normally to operate said element in one direction to select a group, and operating said element in another direction" to find a line in a selected group when prevented from moving the element in the firstmentioned direction.

80. In a telephone system, an automatic switch including a movable element, an operating spring normally tending to move said element in a downward direction, means controlled by said spring for rotating said element when said downward motion is prevented, and electrical circuits for coii' trollin the o eration of said switch:v

31. fn a te ephone system, an automatic- 'right-ang es t selected group, a single operating'means for switch including a-movable element, an operating spring normally tending to move said element in one direction by a continuous motion, means controlled by said spring for moving said element by a con-. tinuous motion in a direction at right-angles to said first-mentioned motion when motion in said direction is prevented, stepby-step means for controlling the extent of motion of said movable element, and electrical circuits for controlling the operation v of said switch.

32. In a telephone system, an automatic switch including a movable element, an operating spring normally tending to move said element in a downward direction by a continuous motion, means controlled by said spring for rotatin said element by a contmuous motion w en said. downward motion is prevented, step-by-step means for controllin the extent of movement of said movable e ement, and electrical circuits for controlling the operation of said switch.

33. In a telephone system, an automatic switch including a movable element, a line relay therefor, and means for intermittently operating said line relay to cause said movable element to operate with a continuous motion.

.34. In a telephone system, lines dividedinto groups, an automatic switch including ,a movable element, a line relay, and means into ii-oops, an automatic switch including a mova le element having mot-ion in oneplane to select ereto ,to find a. line in the moving said element in both of said planes, and a magnet for returning said movable element to normal position 37. In a telephone system. lines divided into groups, an automatic switch including a movable. element. having motion in one plane to select a group and motion in a plane at rightalnglcs thereto to find a line in the selectedgroup, a singlespring for moving said element .in both of said planes, and.

'a magnet for retdrning said movable clctment to normal position. e

38. In a. telephone systenuan automatic switch including a movable element, operating means tending normally to operate said element in one direction, and operating reaps and motion in a plane at the same inapother direction when pre vented from moving it in the first-mentioned direction, a magnet for returning said movable element to normal position, and electrical circuits for controlling said operations.

39. In a telephone system, an automatic switch including a movable element, an operatin spring normally tending to move said uncut-in one directiom means controlled by said spring for movin said element in a direction at right-ang es to said first-mentioned direction when motion in said direction is prevented, a magnet for returning said movable element to normal position, and electrical circuits for controlling said operations.

I 40. In a telephone system, an automatic switch including an operating element movable in but one direction, amovable element cmitrolled by said operating element and adapted to be moved first in one direction and then in a direction atright-angles to said first-mentioned direction by. a single movement of said operatin element, and electrical circuits for controfiing said operations.

41. In a telephone system, an automatic switch, a movable cylinder for said switch, means for moving said cylinder longitudinally, a movable element controlled by said cylinder and adapted to be moved first in 'one direction and then in a direction at right-angles thereto by a single longitudinal movement of said cylinder, and electrical circuits for controlling said operations.

42. In a telephone system, an automatic switch. an operating shaft carrying contact arms. a cylinder mounted upon said shaft, means for moving said cylinder along said shaft,means controlled by said cylinder for first moving said shaft longitudinally and then rotating said shaft during a single longitudinal movement. of said cylinder, and

electrical circuits for controlling said operr ations.

43. In a telephone system, an automatic switch, an operating shaft carrying contact arms, a movable cylinder mounted upon'said shaft. a spiral slot in said cylinder, a pin mounted upon said shaft and adapted 'to ,cngage with said slot. means for moving said cylinder and shaft longitudinally.

movement of said shaft. whereby the longitudinal inovement of the cylinder rotates means for then preventing longitudinal said shaft through the medium of said pin and slot connection. and clccli'ical circuits For controllin said operations.

44. In a te ephone system. lines'dividcd into groups, an automatic switch including i an o eratin there y, a by inder mounted upon said shaft, means for moving said :glinder longitudinally, and means controll by the longitudishaft, contact arms carried" nal movement of said c linder to move said contact arms to first se ect groups and then to find a line in the selected group.

45. In a telephone system, lines divided -into groups, an automatic switch including an 0 crating shaft, contact arms carried there y, a sleeve mounted upon said shaft, s ring-operated means for moving said s eeve downward, means controlled by said downward movement of said sleeve to first move said operating shaft and contact arms carried thereby downward to select a group, and to then rotate said contact arms to find a line in the selected group, and a magnet for returning said shaft and contact arms to normal position.

46. In a telephone system, an automatic switch including an operating shaft, means for moving said shaft in a vertical and rotary direction, a catch for preventing said vertical movement, ,means for normally holding said catch out 'of'e'ngagement with said shaft, means for throwin into engagement with said .sha. t when said shaft is brought to rest after moving from normal position, and electricfl circuits for controlling said operations.

47. In a telephone system, an automatic switch, a notched disk, circuits controlling the operation of said switch, springs engaging the notched surfaces of said disk for contro ling said circuits, means for rotating said disk at a high rate of speed during the operation of said switch to thereby prevent said controlling springs coming in Contact except when said disk is at rest, and electrical circuits for controlling said operations.

48. In an automatic telephone exchange, the combination of a telephone line, an automatic switch, a bridge of the line at said switch including a magnet and a source of current, switching mechanism at the subscribers station for producing either a continuous or an intermittent current in said magnet, means operated by intermittent current in themagnet to actuate the automatic switch to select the terminals of a called subscriber, a relay, means opera ed by continuous current in said magnet after the operation of said switch by said intermittent current for controlling said relay, :1 ringer relay controlled by said first-mentioned relay, a source of ringing current, and means controlled by said ringer relay for connecting the ringing current to the called subscril1c1"s line.

-19. In a telephone system, an automatic switch having a movable element, means for operating said element, a magnet, and mechanical connections between said movable said catchelement and the core of said magnet, whereby the operation of said magnet drives said movable element to normal position.

50. In a telephone system, an automatic selecting switeh'having an element having downward and rotary selecting motions, means for operating said switch, a magnet, and mechanical connections between the core of said magnet and said element, whereby said magnet operates to release said switch by moving said element to normal position.

51. In a telephone system, lines divided into groups, an automatic s- 'i. :h having an element having downward motion to select groups and rotary motion to find a line in the selected group, and a magnet operating to release said switch by moving said element to normal position.

52. In a telephone system, an automatic switch having a movable element, means for moving said element by a continuous motion, step-by-step means for controlling the extent of operation of said movable ele ment, and a solenoid magnet for controlling the release of said-switc 53. In ,a telephone system, an automatic switch having a movable element, means for moving said element by a continuous motion, step-by-step means for controlling the extent of operation of said movable element, a solenoid magnet, and mechanical connections between the core of saidsolenoid and said movable element, whereby said solenoid controls the release of said switch.

54. In a telephone system, an automatic switch including movable arms, means for moving said arms by a continuous motion in two intersecting for controlling the extent of motion of said movable arms, a solenoid magnet, and me chanical connections between the core of said magnet and said movable arms, whereby said solenoid controls the release of said switch.

55. In a telephone system, an automatic switch including a movable element having motion in two intersecting planes, a spring for moving said element in both of said planes, a solenoid magnet, and mechanical connections between the core of said magnet and said movable element, whereby said solenoid controls the release of .said switch.

Signed by us at Chicago, Cook county, Illinois, this 9th day of March, 1912.

JOHN G. BLESSING. BERNARD D. WILLIS. Witnesses:

ARTHUR J. RAY, ALnnn'r' ANoERsEN.

planes, step-by-step means 

